We assume one temporal qualification per statement. Moreover, we assume that implicit temporal qualifications (e.g. tense qualifications) are always made explicit. As an example, we assume that the statement ``They went to Arlington'' is rewritten as ``Sometimes in the past is true that they go to Arlington''. Finally, if the temporal qualification is absent or missing the default qualification is the current time ``now''.
We distinguish between two different types of temporal qualifications, namely, chronologically definite and indefinite temporal qualifications.